MOF-integrated fluorescent composites and adsorbents for rapid detection and removal of date-rape drugs

In this study, a series of fluorescent composites based on the proflavine@metal-organic framework (PF@MOF) for the detection of a common "date-rape drug" was designed and complementarily characterized. The luminescence efficiency was examined in a γ-hydroxybutyric acid (GHB)/ethanol (EtOH)/acetone (Ace) series upon irradiation with 455 nm light. The characteristic green luminescence was noticeable for mixtures containing GHB-Na, and the luminescent effect lasted up to 5 min for the concentrations as low as 6 mg mL^-1. Additionally, to comprehensively characterize the obtained PF@MOF materials, the luminescence kinetics experiments were performed, which showed the persistence of the effect after 4 min of analysis. A significant shift in the absorption maximum and an increase in intensity were found after adding the GHB-Na/EtOH/Ace mixture. The wavelength shift occurs only in the presence of GHB-Na, proving the high selectivity of the developed composites. To comprehensively understand the detection mechanisms, the developed materials were characterized by several characterization and computational methods, including powder X-ray diffraction (PXRD), Raman spectroscopy, Diffuse Reflectance IR Spectroscopy (DRIFTS), low-temperature N₂ sorption, Density Functional Theory (DFT) modeling, and Scanning Electron Microscopy (SEM). Apart from confirmed properties for detecting GHB-Na in alcoholic environments, the parent MOFs have proven to have high GHB-Na adsorption properties. The highest GHB-Na adsorption capacity in water was obtained for defective UiO-66%-25% HCl, reaching 2000 mg g^-1 MOF, whereas in 20% EtOH solution, 3000 mg g^-1 GHB-Na removal was obtained for UiO-25% HCl and functionalized UiO-66-SO₃H. The developed composited materials and their parent counterparts have proven high potential as GHB-Na fluorescent detectors and efficient GHB-Na adsorbents. The unprecedented properties of the obtained materials have revealed their great potential for real-world applications, including the prevention of sexual assault with the use of GHB-Na.